Face-grinding machine



u 30 192 A g 7 A. w. MORTON FACE GRINDING MACHINE 3 Sheets-Sheet 1 FiledNov. 28; 1925 1,640,115 Aug. 3% 1927- A, w.- MORTON FACE GRINDINGMACHINE Filed Nov. 28. 1925 s Sheets$heet2 Aug. 30 1927.

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v A. W..MORTON FACE GRINDING MACHINE Filed Nov. 28, 1925 Z /////4Ill/Ill];

3 Sheets-Shut 3 obj ect-l such Patented Aug. 30, 1927. I

v UNITED STA-res ALLEN w. Monmomfor BALTIMORE, MARYLAND,

:FA'CEGRINDING MACHINE.

. Application file'dNoVeniber 28 19 25. Serial No. 72,006. i

This invention relates to. machines for cable wherever it is necessaryto impart to such an article true plane. surtaces which are accuratelyspaced and in strict parallelism with each other. v

The devhe is particularly intended for grinding the opposed flatsurfaces of piston rings. Since the invent-ion possesses certainpeculiar advantages in this field of use I shall describe it as used ingrinding piston rings in order to develop-its full utility, but it mustbe understood that the invention is applicable to the face grinding ofany article having opposed parallel fiat faces and capable of rotationin the manner hereinafter described. Nhenso used, the device will ottersome or all of the advantages which it has in the particular field ofpiston ring grinding. I

The preferred embodiment of the invention is illustrated inyth'edrawings in which i Fig. 1 isa frontelevation oi theinachine. Fig. 2 isa section of the grinder on th line 22 of Fig. 1.

k an enlarged View of a portion of Fig. 1 with parts broken away toshowthe construrtion of the feed pain. 7

Fig. at is a fragmentary section on the line 4t of Fig; 3. v

i? 5 is View of the worm gear and feed loo trip king from the back ofthe machine.

Fig o is a view oi the work carriersho'wing the ring in position andshowiI-ig the latch. by means of which the carrier may be attached tothe automatic teed.

Generally stated, the machine includes two grinding discs of anysuitable material which are mounted on parallel axes otliset from eachother in such manner that a portion of the tace of one disc is opposedtoa similar portion or: the fare of the other disc. The grinding surfacesare preferably of annular form. that is. cut away at the center, andwhen viewed in sidc'elevation the outer margin of one disc isapproximatelytangent to the inner margin of the other. The work to beground is introduced between the discs and t e discs are fed toward eachother until a definite interval exists between them when the feed stops.

The accuracy with which the work piece is ground is affected by itsrate'and direcof travel relatively to the ais es of the discs and alsoby the rate at which the discs the opposed throes of flat circulargrinding.

discs or rings and is appli-V support or substantially none.

are fed relatively toward each other during Any thin disc or ring,particularly it it be individually cast as the better" grades of pistonrings are, is alm'ost'sure to have internal strains which are relievedby machining and particularly by the side grinding operation. It istherefore important that the grinding pressure exerted on thering be notsuch as to accentuate or perpetuate the distorting efltect of thesestrains,

whether the distortion is initiator develops in the course of thegrinding. The ideal way of relieving the strains is to subject the ringtolight grinding pressure so that the grinding process is slow andsothat the strains may be relieved so gradually that all distortion iscorrected. Such slow grinding is not commercially practicable but an approximately equivalent result can be secured by feeding the grindingelements toward each other first rapidly, then at a decreasing rate, andfinally, when theproper interval is reached, stopping the feedaltogether and allowing the piece tomremain between the discs, when itis finish ground to a truesur- 7 face.

The grinding elementsare rotated in the same direction and, by reason oithis, a rotating couple is always exerted on the work piece in the sameangular direction. This cou ple causes-the work piece to rotate at alltimes and brings every portion of the workpiece into the paths of allportions of the grinding elements. In this way the ring is accuratelyground and the wear is uniformly distributed over the entire faces ofthe grinding elements.

Vlhile this turning couple is effective atall points in the opposedareas'of the two discs, there is lateral thrust on the worl; piece inallpositions between the discs, except one. This one position is that whenthecen-ter of the ring is at the inidlength of a line connecting theaxes of the'discs. In this position the rotating couple-is balanced andthe work piece exerts no thrust on its The worst condition isfreachedwhen the: work piece is adjacent the intersection of the outerperipheries of the two discs. There are two such positions and in eachof them there an undue unbalanced thrust on the-work.

piece.

Ordinarily the grinding discs will be of equal diameters and as this isthe-simplest case for discussion this condition is ascenter line thereis a very slight resultant thrust on the work piece perpendicular to thecenter line. At allother points on the common chord above defined there1s a resultantthrust on the work piece perpendicular to the common'chordandrhence parallel with the center line.. The rotating couple, as hasbeen stated, is efl'ectiveat all points. If the work piece be so guidedthat its center moves on a strai ht line passing through the neutralpoint arid dividing the angle formed by the center line and the commonchord, the resultant thrust exerted by the wheels or discs on the workpiece always has a component in the line of feeding travel and by aproper choiceof direc tion of rotation this can be caused to urge thework piece toward the neutral point.

This can be demonstrated graphically only on a large scale, but theeffect in the operation of the device is pronounced, sufficientlypronounced that in amachine embodying my invention and having a handfedwork carrier the operator can tell when grinding has ceased from thefact that the work piece no longer seeks theneutral position.

After considerable experiment I have found that a satisfactory andprobably the best result is secured when the center of the work piece isguided in a line which passes substantially through the neutral point at'substantiall 15 to the line connectin the centers of the wheels, theneutral point being the m1d-po1nt of such center connecting desirable tohave the work It is usually carrier travel 1n a horizontal path, and toaccomplish this result and yet secure the desired relation of the feedpath to the grinding disc axes, these axes must be offset so that thecenter line above mentioned is inclined. The machine illustrated in thedrawings and now to be described in detail has the discs offset at thepreferred but not the only practicable angle.

The base 11 consists of a hollow casting and is provided with an ofltakeconnection 12 through which particles of metal and abrasive may be drawnoil. The general form of the base is illustrated in the drawings and issubject to considerable variation at the option of the designer.

Mounted on this base at one end is an offset bracket 13, preferablyconstructed as a separate piece, but not necessarily so. This'isinclined upwardly and toward the rear of the machine. The dimensions ofthis bracket determine the' direction and amount of the offset. of thetwo grinding discs, and since the bracket 13 is, held incarriage 16supports combined thrust and radial bearings 17 for a shaft 18, theshaft 18 being supported with its axis parallel with the ways 15' sothat the movements of the carriage 16 in ways 15 shift the shaft 18accurately in the direction of its axis. The carriage 16 may be clampedfast in ways 15 by means of overhanging retaining plates 19 held bybolts 20. A micrometer adjusting screw 21 threaded on a lug 22 oncarriage 16 serves to adjust the position of the carriage accuratelyprior to such clamping. In the operation of the machine carriage 16 isclamped fast, and it is released and shifted only when the machine isbeing adjusted or set up. 3 vAt the opposite end of the base 11 (the endremote from the bracket 13) there are ways provided with gibs 23 whoseguiding surfaces are parallel 'with the ways 15. These support andguidea second carriage 2% and offer means for taking up wear; Thecarriage2l is confined but not clamped by the retaining plates 25. whichin turn are held by bolts 26. g

Mounted on carriage 2 are combined thrust and radial bearings 27 inwhich turns a shaft 28. The axis of the shaft 28 is parallel with theways 23 andhence parallel with the axis of shaft 18. The axes of the twoshafts are offset an amount determined by the design of bracket 13, andin the example illustrated, the shafts are so posi-, tioned that theplane common to the two parallel axes is inclined at to the horizontal.

Each of the shafts l8 and 28 carries a cor responding hub or flange 29,30. To these are fixed by means of screws, or any suitable means,corresponding discs 31, 32 having annular plane facings 33, 34 of anysuitable abrasive material. v

The motion of the carriage 24 toward the carriage .16 is limited by astop screw 35 which is threaded in a lug 36 on carriage 2st in'suchposition that its end collides with a portion of the base 11.

The shafts 18 and 28 carry pulleys 37 and 38 respectively, and throughthese belts 39 and lO drive the shafts and hence the discs 31 and 32 inthe same angular direction and preferably at equal speeds. Guard plates4-1 and 4-2 are fixedly mounted on base 11 and partially house thegrinding discs.

The carriages 16 and 24. project through suitable openings on theseplates.

On the front of base 11 are "horizontal guide ways 43 in which a support44 may be adjustably clamped by means of screws 45.1 A vertical stock 46is clamped in support 44 receive the workpiece, shown in Figs. 2,

and 6 as a ring 51. The blade or carrier 49 and bed 48 have a tongue andgroove engagement indicated at 52 in dotted lines in Fig. 2. The blade49 is further guided by confining cheek plates 53 (see Fig. 2) ward ofdisc 32.

' In order that the blade 49 may be moved manually, a handle 54'isprovided at its fori ward end. It is manually retracted to in'- sert'and remove. work pieces and maybe manually shifted during the grindingoperation if desired, though I provide and consider it better to usemechanical means to accomplish this last named function. Such means areassociated with the general feed" mechanism of the machine and will bede scribed in connection therewith.

The main function of the feed mechanism is to move the disc 32 towardthedisc 31 at an appropriately varying rate, allow it to dwell whilegrinding in its limiting position and then restore the diso'to itsinitial position. The feed then automatically disengages to permit theoperator to remove the finished piece and insert a new one, which theoperator re-engages it.

The shaft 28 carries at its end remote from disc 32 a wide facedpulley55 connected by a belt 56 with a pulley 57 on feed drive shaft 58. Theshaft 58-carries'a worm 59 and must be capable of a swinging movement tocarry the worm 59 into and out of engagement with a worm wheel 60, tostart and stop the feed. Hence, the shaft 58 is mounted near pulley 57in a bearing 61 pivoted at 62 to base 11. The other end of shaft 58 isguided by a yoke 63 swiveled thereon and embracing worm 59, the yoke 63being steadied by pivotal connection at (i llo a swinging arm 65,supported on base 11. The thrustof the worm is taken by collars 66 atbearing 61 and sufficient clearance is allowed between the yoke andtheends of the worm to permit the swinging movement described.

he yoke 63 is capable oflimited downward motion and is constantly-urgedclownward by a spring 67. It may be drawn upward to mesh the worm withthe wheel) and there retained,v by the camming and latching, action of abeveled latch nose 68 upon a beveled lug 69 on yoke 63. The latch nose68 is fixed to'a-bell crank having a horizontal arm-70 and asubstantially ver after tical arm 71. The arm 70 is connected by link72, l'ever 7 3 and link 74 with a treadle 75 pivotallysupported at 76 ona bracket 77 which is carried by base 11. Depression of .the'pedalcauses latch nose 68 to engage lug :69 and lift yoke 63. In the latchedpositions the parts areretained by friction of the members 68 and 69 andare automatically disengaged upon the completion of the grinding cycieby means associated with the worm wheel 60, when the weight 78v hung onlever 73 pulls latch nose 68 away from lug69. v The worm wheel'60 ismounted toflturn freely. on a stub shaft 7 9 fixed in base 11, and:lined to wornrwheel 60 to turn therewith is a cam 8Q which controls thefeed of'car- 'riage-24' and aib'cvel gear 81*which drives the workcarrier or blade 49. The form of cam -is quite clearly shown in The camturns clockwise (as viewed'in Figs. 1 and-3) and coactswith a followerplate. 82 on lever 83. The lever 83 is adjustably fixed on shaft 84 bymeans of themachine screw85 which clamps a slottedvend'of the leveruponthe shaft. The shaft 84 turns in bearings 86in base 11 and carries apinion 87 which'meshes with rack 881 011- the lower side of' carriage24,.- A weight 89 constantly urges lever 83 downward, urging carriage24toward carriage 16, with sufficient pressure thustransmitted .to theabrasive to grind the workpiece. I The cam follower plate 82 is not,fixed on lever83 but is pivoted thereto at 90 and is adjusted relativelythereto by screw '91. A confining guide 92 gives lateral support tofollower plate 82. Ordinary adjustments are made by screw9l. Adjustmentsbeyond the range of screw 91 are made by loosening screw 85 and shiftinglever 83 on shaft 84.

In Fig. 3 the cam is shown in the position assumed between, grindingoperations, in which thelever 83 is held elevated, thus retracting disc32 for the removal and insertion. of work pieces. As the cam rotatesfrom thisposition the lever 83 is lowered, first quite rapidly and thenslower and slower. Before, the cam has brought its smallestradius intocontact with the follower, screw 35'arrests carriage 24 and from then onuntil the-nose lifts follower 82 once more, the discs grind at fixedspacing gauged by the screw 35 and the cam revolves free of. thefollower 82. The length of time in which the cam revolves free of thefollower, or conversely-"the time taken to bring the discs together,affects the final thickness and accuracy of the work piece to some. ex-

tent. Therefore, by means of screw 91 very accurate adjustments can bemade, determined by ,the point at. which cam breaks away from followeras screw 35 hits base and. carriage 24 reaches its maximum inward travelorthe: totalforce of weight 89 presses the carriage 24 against the workpiece, which, due to its unfinished thickness, holds the discs apart andarrests the inward travel vMounted in bearings'98 on base 11 is a shaft99. This carries a bevel gear 100 which meshes with bevel gear 81 andserves to rotate shaft 99 wheneverworm 59'is engaged with wheel 60. Theshaft 99 carries an eccentric 101. A stra 102 encircles eccentric 101and is connected by a'rod 103 with a lever 104. The eccentric 101 isangularly adjustable on shaft 99. being held by a set screw 105, and thestrap. 102 and its rod 103 are threaded together and locked by check nutas shown at 106, so that the effective length of the eccentric rod isadjust able. The arm 104 is fixed on a shaft 107 which turns in bearings108, on post 46, and 109 supported by frame 11 and guard plate ll secondarm 110 is adjustably fixed by means of a set screw 1-11 on shaft 107and is operatively connected to move the work carrier blade back andforth. Such connection is releasable and includes a latch arm 112pivoted to carrier 49 at 113 and having an actuating trigger 114:. Thelatch arm 112 has a notch 115 to receive a pin 116 projecting laterallyfrom arm 110. This pin 116 is adjustable toward and from shaft, 107 tovary the effective radius of 110, by means of slot 117 and nut 118.Thus, by means of the angular adjustment of the eccentric 101 and theadjustment ot'the efiective length of eccentric rod 103, together withthe angular adjustment of the arm 110 on its shaft 107, an adjustablestroke of the work carrier 4-9 is provided to take care of *arious sizework pieces as Well'as to determine the starting or stopping point ofthe grinding cycle.

By changing the gear ratios of the bevel gears 81 and 100. a greater orlesser number of strokes of the carrier plate per grinding cycle may behad as well as a variable start-,

toward the neutral point, the feed of the wheels toward eachotherterminating at or substantially at the time the work carrierreverses its lIlO-tlOIL From this'it follows is distributed so that thediscs are subjected to substantially unifprm wear throughout theireffective areas; and so that a relatively long lapping. periodi'ssecured. j V In the operation of the device both grind} ing discs arerotated constantly. YVhen the ieedis at rest and. the discs. separated,the

operator releases latch 112 bytrigger 114i. and drawscarrier; l9 towardhim. :He then inserts a ring to be ground in' 'hole 50, piushes carrier1 9 to the rear, engages latch 112 with pin116 and then depressestreadle '75. De-

pression of the treadle connectsthe reed drive so that carr er19 isreclprocate'd and carriage 24 feeds toward carriage 16 with the motion.

nationof two discs having plane grinding.

facesg'nieans for supporting and rotating said discs in the same angulardirection about ol'lset parallel axes, with portions of said discsopposed'to and parallel with each a other; and afwork carrier arrangedto support workpiece for rotation about an axis parallel with the axesof said discs and to guide the same in a path between said discs whichis oblique to the line connecting the axes of said discs and whichapproximately bisects said line. r r

2. In a face grinding machine, the combination of two discs having planegrinding faces;; means for-supporting and rotating said discs in thesame angular'direction about oii'set parallel axes, with portions ofsaid discs opposed to and parallel with each other; and a work carrierarranged to support a work piece for rotation about an axis parallelwith the axes of said discs and to guide the same in a straight linewhich bisects the line connecting the axes ofsaid discs and makes anangle of 15 therewith.

In a face grinding machine, the combination of two discs having planegrinding faces; means for supporting and rotating said discs aboutoffset parallel axes with portions of said discs opposed to and parallelwith each other; a work carrier arranged to support an axis parallelwith the axes of said disc, and to guide the same in a path between saiddiscs which is oblique to the line connecting the axes of said discs andwhich approximately bisects said line and automatic feed .means'constructed and arranged to move said discs relatively toward each otherat a variable rate, then, when a definite. interval between said discsis reached, to arrest'such movement, and finally after an'interval ofrest to separate said discs.

4.- In face grinding machine, the combination of two discs having planegrinding faces; means for supporting and rotating said discs in the samedirection about offset parallel axes with portions of said discs opposedto and parallel with each other; a

work carrier movable between the opposed portions'of said discs andhaving an opening in which a work piece may be rotatably cone fined; andautomatic means for reciprocating said carrier in a substantially rightline path which is oblique to and which approxlmately bisects the lineconnecting the axes of said discs. v

5. in a face grinding machine, the combination of two discs-having planegrinding faces; means for supporting and rotating said discs in the samedirection about offset parallel axes with portions of said discs opposedto and parallel with each other; a

work carrier movable between the opposed portions of said discs andhaving a circular opening in which a work piece may be confined andpermitted to rotate about an axis parallel with the axes of said discs;and automatic means for traversing said work carrier, the parts being soarranged that the work piece moves in a path oblique to the lineconnecting the axes of said discs and substantially bisecting the same.

6. In a face grinding machine, the combination of two discs having planegrinding faces; means for supporting and rotating said discs in the samedirection about offset parallelaxes with portionsof said discs opposedto and parallel with each other; a work carrier movable between the awork piece for rotation about- 1portio'ns of said an openlng in which awork piece may be confined and permitted to rotate about an axisparallel with the axes of said discs;

automatic means for traversing said carrier and a manually operablereleasable connection between said traversing means and said carrier;

7. In a face grinding machine, the'combination oftwo discs having planegrinding faces; means forsupporting and rotating said discs about offsetparallel axes with faces opposed to and parallel with each other; afeeding'mechanism arranged to move said discs relatively towardeachother until a definite interval between said discs is reached andthereafter to dwell and then separate said discs; a work carrier movablewith a reciprocating motionbetween the opposed portions of said discsand having a portion in which a work piece may be confined and permittedto rotate about an axis parallel with the axes of said discs, anddriving connections for said feeding means and for said work carrier.

8. In a face grinding machine, the combination of two discs having planegrinding faces; means for supporting and rotating said discs aboutoffset parallel axes with portions of said faces opposed to and'parallelwith each other; a feeding mechanism arranged to move said discsrelatively toward each other until a definite interval between saiddiscs is reached and thereafter to dwell and then separate said discs; awork carrier movable between the opposed portions of said discs andhaving a portion in which a work piece may be confined and permitted torotate about an axis parallel with the axes of said discs; drivingconnections for said feeding means and for said work carrier; startingmeans under the control of the operator for establishing said drivingconnections; and automatic interriipting means ararngedto terminate saiddriving connection upon the separation of said discs.

Intestimony whereof I have signed my name to this specification.

ALLEN W. MORTON.

